This invention relates to high pressure reciprocating pumps such as those used to pump drilling mud in the oil production industry, including those pumps commonly referred to in the industry as mud and slush pumps. In particular, the invention relates to a piston rod assembly, suitable for rapid replacement between a power end and a fluid end of a reciprocating pump.
It is necessary with high pressure reciprocating pumps to replace the piston or other dynamic component with relative regularity and it is therefore advantageous if this task can be performed quickly and easily. Typical quick release piston rod assemblies, such as those disclosed in GB 2,190,170 and U.S. Pat. No. 5,904,701, have axially arranged links to the power and fluid ends, held in place by radial pins. Tension is then applied to the pins via axial pistons to couple the fluid and power ends together.
A disadvantage of these assemblies is that connectors with suitably sized apertures must be arranged at each of the power and fluid ends. The use of radial pins, to which longitudinal tension is applied, provides weak points on the assembly which can be prone to fracture during high reciprocation. A further disadvantage of these assemblies is that the relative angle between the power end and fluid end must be taken into account when positioning the assembly.